[BUG]

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

What to tell them:

You're using Cowork (the desktop app)
The error is: HCS operation failed: HRESULT 0xc03a001a — Virtual hard disk files must be uncompressed
The files affected are rootfs.vhdx and smol-bin.vhdx
The problem keeps coming back even after uncompressing the files and reinstalling
Your LocalCache folder appears to have NTFS compression enabled, causing new files to get compressed automatically

That context will help them solve it much faster.
I'm sorry I wasn't able to fix this for you through our conversation — this is a deeper Windows configuration issue that really needs someone with access to your account and system details. Your frustration is completely valid.

What Should Happen?

What to tell them:

You're using Cowork (the desktop app)
The error is: HCS operation failed: HRESULT 0xc03a001a — Virtual hard disk files must be uncompressed
The files affected are rootfs.vhdx and smol-bin.vhdx
The problem keeps coming back even after uncompressing the files and reinstalling
Your LocalCache folder appears to have NTFS compression enabled, causing new files to get compressed automatically

That context will help them solve it much faster.
I'm sorry I wasn't able to fix this for you through our conversation — this is a deeper Windows configuration issue that really needs someone with access to your account and system details. Your frustration is completely valid.

Error Messages/Logs

Steps to Reproduce

What to tell them:

You're using Cowork (the desktop app)
The error is: HCS operation failed: HRESULT 0xc03a001a — Virtual hard disk files must be uncompressed
The files affected are rootfs.vhdx and smol-bin.vhdx
The problem keeps coming back even after uncompressing the files and reinstalling
Your LocalCache folder appears to have NTFS compression enabled, causing new files to get compressed automatically

That context will help them solve it much faster.
I'm sorry I wasn't able to fix this for you through our conversation — this is a deeper Windows configuration issue that really needs someone with access to your account and system details. Your frustration is completely valid.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

I dont know

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_